Table 3.
Linear mixed effects models results comparing N-acetylcysteine to placebo on primary and secondary brain metabolite levels in the dorsal anterior cingulate cortex of adolescents who drink heavily.
| Metabolite | Fixed effect | Estimate | Std. error | DF | T-value | p value | η2p (95% CI) |
|---|---|---|---|---|---|---|---|
| Glx | |||||||
| Medication | −0.03 | 0.23 | 29.31 | −0.14 | 0.89 | <0.01 (0.00–0.09) | |
| Sequence | 0.09 | 0.37 | 25.45 | 0.24 | 0.81 | ||
| Visit | 0.10 | 0.12 | 30.39 | 0.85 | 0.40 | ||
| Baseline Glx | 0.07 | 0.08 | 25.49 | 0.79 | 0.44 | ||
| GM:BM | −2.81 | 4.68 | 27.66 | −0.60 | 0.55 | ||
| Cannabis use days | −0.18 | 0.30 | 36.47 | −0.58 | 0.57 | ||
| AUD | 0.33 | 0.35 | 25.44 | 0.95 | 0.35 | ||
| GABA+a | |||||||
| Medication | 0.01 | 0.11 | 54.00 | 0.07 | 0.94 | <0.01 (0.00–0.03) | |
| Sequence | 0.04 | 0.11 | 54.00 | 0.34 | 0.74 | ||
| Visit | −0.06 | 0.05 | 54.00 | −1.16 | 0.25 | ||
| Baseline GABA+ | 0.11 | 0.13 | 54.00 | 0.86 | 0.39 | ||
| GM:BM | −2.39 | 1.67 | 54.00 | −1.43 | 0.16 | ||
| Cannabis use days | −0.01 | 0.12 | 54.00 | −0.07 | 0.95 | ||
| AUD severity | −0.07 | 0.06 | 54.00 | −1.26 | 0.21 | ||
| GSH | |||||||
| Medication | 0.07 | 0.08 | 25.20 | 0.84 | 0.41 | 0.03 (0.00–0.24) | |
| Sequence | −0.06 | 0.14 | 22.91 | −0.43 | 0.67 | ||
| Visit | 0.05 | 0.04 | 27.18 | 1.26 | 0.22 | ||
| Baseline GSH | 0.08 | 0.19 | 23.18 | 0.42 | 0.68 | ||
| GM:BM | −1.17 | 1.99 | 26.14 | −0.59 | 0.56 | ||
| Cannabis use days | 0.02 | 0.14 | 45.91 | 0.11 | 0.91 | ||
| Binge drinking episodes | 0.07 | 0.04 | 47.99 | 1.81 | 0.08 | ||
| Glu | |||||||
| Medication | −0.13 | 0.16 | 28.11 | −0.82 | 0.42 | 0.02 (0.00–0.22) | |
| Sequence | −0.00 | 0.25 | 24.97 | 0.01 | 0.99 | ||
| Visit | 0.04 | 0.08 | 29.67 | 0.52 | 0.61 | ||
| Baseline Glu | 0.10 | 0.08 | 25.19 | 1.28 | 0.21 | ||
| GM:BM | −4.20 | 3.33 | 27.48 | −1.26 | 0.22 | ||
| Cannabis use days | 0.09 | 0.22 | 39.64 | 0.40 | 0.69 | ||
| Binge drinking episodes | −0.11 | 0.06 | 46.72 | −1.76 | 0.08 | ||
| tNAA | |||||||
| Medication | −0.10 | 0.10 | 29.38 | −1.02 | 0.31 | 0.03 (0.00–0.23) | |
| Sequence | −0.22 | 0.16 | 25.64 | −1.34 | 0.19 | ||
| Visit | −0.04 | 0.05 | 30.63 | −0.87 | 0.39 | ||
| Baseline tNAA | 0.62 | 0.11 | 25.61 | 5.60 | <0.001 | ||
| GM:BM | −1.09 | 2.32 | 28.36 | −0.47 | 0.64 | ||
| Cannabis use days | 0.13 | 0.15 | 29.29 | 0.90 | 0.37 | ||
| AUD | −0.34 | 0.17 | 25.57 | −1.99 | 0.06 | ||
| tCho | |||||||
| Medication | −0.03 | 0.03 | 29.36 | −0.91 | 0.37 | 0.03 (0.00–0.21) | |
| Sequence | −0.03 | 0.04 | 25.60 | −0.68 | 0.50 | ||
| Visit | 0.01 | 0.01 | 30.49 | 0.81 | 0.42 | ||
| Baseline tCho | 0.98 | 0.11 | 26.20 | 9.16 | <0.001 | ||
| GM:BM | −1.92 | 0.60 | 27.97 | −3.18 | 0.004 | ||
| Cannabis use days | −0.04 | 0.04 | 28.06 | −0.90 | 0.37 | ||
| AUD | −0.08 | 0.04 | 25.51 | −1.83 | 0.08 | ||
| tCr | |||||||
| Medication | 0.08 | 0.08 | 29.48 | 0.94 | 0.35 | 0.03 (0.00–0.22) | |
| Sequence | −0.14 | 0.16 | 26.81 | −0.87 | 0.39 | ||
| Visit | 0.00 | 0.04 | 30.41 | 0.04 | 0.97 | ||
| Baseline tCr | 0.59 | 0.15 | 27.13 | 3.93 | <0.001 | ||
| GM:BM | −3.05 | 2.33 | 31.90 | −1.31 | 0.20 | ||
| Cannabis use days | 0.07 | 0.14 | 47.79 | 0.49 | 0.62 | ||
| Drinks per drinking day | −0.04 | 0.03 | 50.29 | −1.73 | 0.09 | ||
| mI | |||||||
| Medication | −0.07 | 0.11 | 29.42 | −0.59 | 0.56 | 0.01 (0.00–0.18) | |
| Sequence | −0.18 | 0.19 | 26.42 | −0.97 | 0.34 | ||
| Visit | −0.04 | 0.06 | 30.12 | −0.78 | 0.44 | ||
| Baseline mI | 0.51 | 0.14 | 26.56 | 3.58 | 0.001 | ||
| GM:BM | −0.64 | 2.64 | 30.20 | −0.24 | 0.81 | ||
| Cannabis use days | 0.01 | 0.17 | 42.69 | 0.06 | 0.95 | ||
| Drinks per drinking day | −0.02 | 0.03 | 53.26 | −0.68 | 0.50 | ||
n = 31 for glutamate + glutamine (Glx), GABA+, and other secondary metabolites; n = 28 for glutathione (GSH). References: medication = placebo; sequence = placebo/N-acetylcysteine; visit = visit 4 (last MRI visit).
Glu glutamate, tNAA total N-acetylaspartate, tCho total choline-containing metabolites, tCr total creatine-containing metabolites, mI myo-inositol, AUD alcohol use disorder, GM:BM brain tissue composition [GM/(GM + WM)], η2p partial eta squared (reported only for medication).
Bold values indicate statistical significance.
aRandom intercepts were not appropriate for this model, resulting in higher degrees of freedom.